"Bald Eagle" <cre### [at] netscapenet> wrote:
> "And" <49341109@ntnu.edu.tw> wrote:
> > And then, anyone know why the wood grains becomes so white(or ever saw the same
> > ) on my last post image(dsc_0814)? I don't know why.
>
> What you're seeing there is oxidation of the paint, or a frosting or "bloom"
> from when solvent gets on the surface and dissolves out some of the clear
> binder, or when water gets on the paint and hydrates/swells the surface coating,
> which I believe causes it to develop microscopic cracks, allowing air in, and
> giving it a different IOR.
> Kind of like taking transparent tape and putting it on a dark surface - it's not
> transparent until you rub/burnish it down to exclude all of the air between the
> tape and the surface.

Wow!
Are you an expert of chemical?

>
> > ------------------------------------------------------------------
> > If I can simulate the most of the wood pattern detail like this attached pic
>
> I think that what might have to happen is to have a variety of functions that
> get interpolated across the surface of the wood, to give rise to a smooth
> blending of different patterns.   Right now you're just sort of unioning them.
>
> > I have many reasons.
> > The one reason is that I need correct information about the f_bumps pattern.
>
> What needs to be corrected?

Because I found many beautiful pattern this week, including something
radial-randomize or circular-randomize bump pattern. They are useful and play an
important role.
Maybe my program can automatically pick them(the parameter of control where the
large-value color-block appear), fitting the shape of the woodgrain
angular-shape curve you make. I think maybe they have relation...

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